Phagocytosis by macrophages. I. Kinetics of adhesion between particles and phagocytes

A quantitative method for measuring the initial rate of adhesion of foreign particles to mouse peritoneal macrophages, using protein-coated paraffin oil particles, is described. It was performed to measure the rate of adhesion, which is the first step of phagocytosis, separately from the other phagocytic activities. Kinetic studies showed that the cell-substrate adhesion was a Michaelis-Menten type reaction, which has two rate indices, Km and V. The effects of various reagents on the adhesion rate were analysed. KCN and NaN3 change the rate by affecting V, while the changes in the rate brought about by chlorpromazine and filipin are due to their effect on the Km. Cytochalasin B decreased the adhesion rate, but colchicine did not. The initial rate of adhesion decreased with decreasing temperature. As Arrhenius plot of the initial rate showed a break at 30 degrees C, and gave an activation enthalpy of 14.8 kcal for the process at the physiological temperature. No characteristic change in membrane fluidity was found at 30 degrees C using electron spin resonance spectroscopy.